This article represents a multidisciplinary approach to biomechanics (engineering + medicine) in the field of "collum femoris" fractures. One possible treatment method for femoral neck fractures, especially for young people, is the application of cancellous (i.e. lag or femoral) screws (with full or cannulated cross-section) made of Ti6Al4V or stainless steel. This paper therefore aims to offer our own numerical model of cancellous screws together with an assessment of them. The new, simple numerical model presented here is derived together with inputs and boundary conditions and is characterized by rapid solution. The model is based on the theory of beams on an elastic foundation and on 2nd order theory (set of three differential 4th order equations, combination of pressure and bending stress-deformation states). It presents the process for calculating displacements, slopes, bending moments, stresses etc. Two examples (i.e. combinations of cancellous screws with full or cannulated cross-section made of stainless steel or Ti6Al4V material) are presented and evaluated (i.e. their displacement, slopes, bending moments, normal forces, shearing forces and stresses). Future developments and other applications are also proposed and mentioned.

Department of Applied Mechanics Faculty of Mechanical Engineering VSB Technical University of Ostrava 17 listopadu 15 2172 708 33 Ostrava Czech Republic

Trauma Centre University Hospital Ostrava 17 listopadu 1790 708 52 Ostrava Czech Republic

See more in PubMed

Bartoníček J, Džupa V, Skála-Rosenbaum J, Pazdírek P. Femoral Neck Fractures of Adults—Summary, (Zlomeniny krčku femuru u dospělých- souhrnný referát) Úrazová chirurgie. 2003;11(3):10–23.

Frihagen F, Madsen JE, Reinholt FP, Nordsletten L. Screw augmentation in displaced femoral neck fractures clinical and histological results using a new composite. International Journal of the Care of the Injured. 2007;38:797–805. doi: 10.1016/j.injury.2007.03.005. PubMed DOI

Frydrýšek, K. (2011). Probabilistic approaches applied in the solution of problems in mining and biomechanics. In Engineering Mechanics 2011, pp. 151–154, Svratka, Czech Republic, ISBN: 978-80-87012-33-8.

Frydrýšek, K., Jořenek, J., Učeň, O., Kubín, T., Žilka, L., Pleva, L. (2012). Design of external fixators used in traumatology and orthopaedics—treatment of fractures of pelvis and its acetabulum. Procedia Engineering, 48, 164–173. 10.1016/j.proeng.2012.09.501

Hawks MA, Kim H, Strauss JE, Oliphant BW, Golden RD, Hsieh AH, Nascone JW, O’Toole RV. Does a trochanteric lag screw improve fixation of vertically oriented femoral neck fractures? A Biomechanical Analysis in Cadaveric Bone, Clinical Biomechanics. 2013;28(8):886–891. PubMed

Hoza P, Hála T, Pilný J. Fractures of proximal femur and their solution, (Zlomeniny proximálního femuru a jejich řešení) Medicína pro praxi. 2008;5(10):393–397.

Hrubina M, Horák Z, Bartoška R, Navrátil L, Rosina J. Computational modeling in the prediction of dynamic hip screw failure in proximal femoral fractures. Journal of Applied Biomedicine. 2013;11:143–151. doi: 10.2478/v10136-012-0017-8. DOI

Kraus J, Volf V, Burget F, Jindrová B. PCCP versus standard proximal femoral nail in the treatment of pertrochanteric femoral fractures (PCCP versus standardní proximální femorální hřeb při léčbě pertrochanterických zlomenin femuru) Rozhl Chir MEDLINE. 2009;88(8):469–474. PubMed

Leonard, M., Alao, U., Glynn, A., Dolan, M. (2009). Hip fractures: Failure of fixation and outcome of salvage arthroplasty. European Journal of Orthopaedic Surgery & Traumatology. 10.1007/s00590-009-0468-0

Nabhani, F., Bradley, E.J., Hodgson, S. (2010). Comparison of two tools for the measurement of interfragmentary movement in femoral neck fractures stabilised by cannulated screw. Robotics and Computer-Integrated Manufacturing, 26(6), 610–615. 10.1016/j.rcim.2010.06.014

Skála–Rosenbaum, J., Bartoníček, J., Říha, D., Waldauf, P., Džupa, V. (2011). Single-Centre Study of Hip Fractures in Prague, Czech Republic, 1997–2007. International Orthopaedics, 35(4), 587–593. 10.1007/s00264-010-0984-x PubMed PMC

Skála-Rosenbaum J, Džupa V, Bartoníček J, Douša P, Pazdírek P. Osteosynthesis of intracapsular femoral neck fractures, (Osteosyntéza intrakapsulárních zlomenin krčku femuru) Rozhl Chir MEDLINE. 2005;84(6):291–298. PubMed

Waaler Bjørnelv, G.M., Frihagen, F., Madsen, J.E., Nordsletten, L., Aas, E. (2012). Hemiarthroplasty compared to internal fixation with percutaneous cannulated screws as treatment of displaced femoral neck fractures in the elderly: Cost-utility analysis performed alongside a randomized, controlled trial. Osteoporosis International, 23(6), 1711–1719. 10.1007/s00198-011-1772-1 PubMed

Xarchas, K.C., Staikos, C.D., Pelekas, S., Vogiatzaki, T., Kazakos, K.J., Verettas, D.A. (2007). Are Two Screws Enough for Fixation of Femoral Neck Fractures? A Case Series and Review of the Literature, The Open Orthopaedics Journal, 1, 4–8, ISSN: 1874-3250, 10.2174/1874325000701010004 PubMed PMC

Hendrych A, Kvíčala M, Matolín V, Životský O, Jandačka P. The influence of vanadium microalloying on voids occurrence in low-alloyed cr-mo steels after continuous casting. International Journal of Fracture. 2011;168(2):259–266. doi: 10.1007/s10704-010-9573-7. DOI

Frydrýšek, K., Tvrdá, K., Jančo R. et al. (2013). Handbook of Structures on Elastic Foundation, VŠB—Technical University of Ostrava. Ostrava, Czech Republic, 1-1691, ISBN 978-80-248-3238-8

Marek, P., Brozetti, J., Guštar, M., Tikalsky P. et al (2003). Probabilistic assessment of structures using Monte Carlo simulation (2nd edition), pp. 1–471. Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prague, Czech Republic, ISBN 80-86246-08-6, (CD attached).

Frydrýšek, K. (2014). Strength analyses of full and cannulated femoral screws made up from stainless steel and Ti6Al4V, calculation report, pp. 1–43, FME VŠB-Technical University of Ostrava, Ostrava, Czech Republic.

MEDIN a.s. (2017) http://www.medin.cz/7--1

Filipov, O. (2012). Biomechanics of the fractured femoral neck—the new BDSF-method of positioning the implant as a simple beam with an overhanging end. Injury and Skeletal Biomechanics, Chapter 5, pp. 81–93. InTech, 10.5772/47839. ISBN 978-953-51-0690-6

Filipov, O. (2011). Biplane double-supported screw fixation (F-technique): a method of screw fixation at osteoporotic fractures of the femoral neck. European Journal of Orthopaedic Surgery & Traumatology, 21(7), 539–543. 10.1007/s00590-010-0747-9 PubMed PMC

Jančo, R., & Kováčova, M. (2005). Using packages mechanics explorers ‘Beam’. In Program Mathematica for Solution of Euler-Bernoulli Beams. In 4th International Conference on APLIMAT 2005, pp. 197–203, Bratislava, Slovakia, ISBN:978-80-969264-2-8

Michenková, Š., Frydrýšek, K., & Nikodým, M. (2014). Straight beams rested on nonlinear elastic foundations—part 2 (numerical solutions, results and evaluation). Applied Mechanics and Materials, 684, 21–29. www.scientific.net/AMM.684.21

Labudková, J., & Čajka, R. (2016). Comparison of analysis of linear inhomogeneous and nonlinear half-space in foundation-subsoil interaction. International Journal of Mechanics, 10, 90–98.

Morávkova, Z., Tomečková, I., & Frydrýšek, K. (2017). Beam rested on unilateral elastic foundation—(theory, experiments and finite element approach). In Engineering Mechanics 2017 (23rd International Conference on Engineering Mechanics), pp. 670–673, Svratka, Czech Republic, ISBN:978-80-214-5497-2, ISSN: 1805-8248

Gałka, A., Telega, J.J., & Tokarzewski, S. (1999). Application of homogenization to evaluation of effective moduli of linear elastic trabecular bone with plate-like structure. Archives of Mechanics, 51(3–4), 335–355

Pérez-González A, Fenollosa-Esteve C, Sancho-Bru JL, Sánchez-Marín FT, Vergara M, Rodríguez-Cervantes PJ. A modified elastic foundation contact model for application in 3D models of the prosthetic knee. Medical Engineering & Physics. 2008;30:387–398. doi: 10.1016/j.medengphy.2007.04.001. PubMed DOI

Fregly BJ, Bei Y, Sylvester ME. Experimental evaluation of an elastic foundation model to predict contact pressures in knee replacements. Journal of Biomechanics. 2003;36:1659–1968. doi: 10.1016/S0021-9290(03)00176-3. PubMed DOI

Halloran JP, Easley SK, Petrella AJ, Rullkoetter PJ. Comparison of deformable and elastic foundation finite element simulations for predicting knee replacement mechanics. Journal of Biomechanical Engineering. 2005;127:813–818. doi: 10.1115/1.1992522. PubMed DOI

Bechtold JE, Riley DR. Application of beams on elastic foundation and B-spline solution methodologies to parametric analysis of intramedullary implant systems. Journal of Biomechanics. 1991;24(6):441–448. doi: 10.1016/0021-9290(91)90032-I. PubMed DOI

Čada, R., Frydrýšek, K., Sejda, F., Demel, J., & Pleva, L. (2017). Analysis of locking self-taping bone screws for angularly stable plates. Journal of Medical and Biological Engineering, 37(4), 612–625. 10.1007/s40846-017-0279-4 PubMed PMC

Winczek, J., Gawronska, E., Murcinkova, Z., Hatala, M., Pavlenko, S., & Makles, K. (2017). Analysis of thermomechanical states in single-pass GMAW surfaced steel element. In AIP Conference Proceedings 1822 (9th Polish National Conference on Applied Mechanics), 020015, pp. 1–13, Poland 10.1063/1.4977689

Bergmann G, Deuretzbacher G, Heller M, Graichen F, Rohlmann A, Strauss J, Duda GN. Hip contact forces and gait patterns from routine activities. Journal of Biomechanics. 2001;34(7):859–871. doi: 10.1016/S0021-9290(01)00040-9. PubMed DOI

Pauwels F. Biomechanics of the locomotor apparatus: contribution on the functional anatomy of the locomotor apparatus. Berlin: Springer; 1980.

Frydrýšek, K., Václavek, L. (2016). Stochastic computer approach applied in the reliability assessment of engineering structures. Advances in Intelligent Systems and Computing, 451, 121–129

Lokaj, A., & Vavrušová, K. (2011). Contribution to the probabilistic approach of the impact strength of wood. In Engineering Mechanics 2011, pp. 363–366. Svratka, Czech Republic, ISBN: 978-80-87012-33-8.